On Tue, Dec 17, 2019 at 05:32:59PM +0000, Al Viro wrote:
> No. This is simply wrong - as it is, there's no difference between
> "foo" and "foo=". Passing NULL in the latter case is wrong, but
> this is not a good fix.
>
> This
> if (v_size > 0) {
> param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
> if (!param.string)
> return -ENOMEM;
> }
> should really be
> if (value) {
> param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
> if (!param.string)
> return -ENOMEM;
> }
> and your chunk should be conditional upon value, not v_size. The
> same problem exists for rbd.c
How about this (completely untested):
Pass consistent param->type to fs_parse()
As it is, vfs_parse_fs_string() makes "foo" and "foo=" indistinguishable;
both get fs_value_is_string for ->type and NULL for ->string. To make
it even more unpleasant, that combination is impossible to produce with
fsconfig().
Much saner rules would be
"foo" => fs_value_is_flag, NULL
"foo=" => fs_value_is_string, ""
"foo=bar" => fs_value_is_string, "bar"
All cases are distinguishable, all results are expressable by fsconfig(),
->has_value checks are much simpler that way (to the point of the field
being useless) and quite a few regressions go away (gfs2 has no business
accepting -o nodebug=, for example).
Partially based upon patches from Miklos.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 2b184563cd32..9fc686be81ca 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -6433,7 +6433,7 @@ static int rbd_parse_options(char *options, struct rbd_parse_opts_ctx *pctx)
if (*key) {
struct fs_parameter param = {
.key = key,
- .type = fs_value_is_string,
+ .type = fs_value_is_flag,
};
char *value = strchr(key, '=');
size_t v_len = 0;
@@ -6443,14 +6443,11 @@ static int rbd_parse_options(char *options, struct rbd_parse_opts_ctx *pctx)
continue;
*value++ = 0;
v_len = strlen(value);
- }
-
-
- if (v_len > 0) {
param.string = kmemdup_nul(value, v_len,
GFP_KERNEL);
if (!param.string)
return -ENOMEM;
+ param.type = fs_value_is_string;
}
param.size = v_len;
diff --git a/fs/fs_context.c b/fs/fs_context.c
index 138b5b4d621d..9097421cbba5 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -175,14 +175,15 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key,
struct fs_parameter param = {
.key = key,
- .type = fs_value_is_string,
+ .type = fs_value_is_flag,
.size = v_size,
};
- if (v_size > 0) {
+ if (value) {
param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
if (!param.string)
return -ENOMEM;
+ param.type = fs_value_is_string;
}
ret = vfs_parse_fs_param(fc, ¶m);
diff --git a/fs/fs_parser.c b/fs/fs_parser.c
index d1930adce68d..65842cd2e320 100644
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -85,7 +85,6 @@ int fs_parse(struct fs_context *fc,
const struct fs_parameter_enum *e;
int ret = -ENOPARAM, b;
- result->has_value = !!param->string;
result->negated = false;
result->uint_64 = 0;
@@ -95,7 +94,7 @@ int fs_parse(struct fs_context *fc,
* "xxx" takes the "no"-form negative - but only if there
* wasn't an value.
*/
- if (result->has_value)
+ if (param->type != fs_value_is_flag)
goto unknown_parameter;
if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2])
goto unknown_parameter;
@@ -127,14 +126,13 @@ int fs_parse(struct fs_context *fc,
case fs_param_is_u64:
case fs_param_is_enum:
case fs_param_is_string:
- if (param->type != fs_value_is_string)
- goto bad_value;
- if (!result->has_value) {
+ if (param->type == fs_value_is_string)
+ break;
+ if (param->type == fs_value_is_flag) {
if (p->flags & fs_param_v_optional)
goto okay;
- goto bad_value;
}
- /* Fall through */
+ goto bad_value;
default:
break;
}
@@ -144,8 +142,7 @@ int fs_parse(struct fs_context *fc,
*/
switch (p->type) {
case fs_param_is_flag:
- if (param->type != fs_value_is_flag &&
- (param->type != fs_value_is_string || result->has_value))
+ if (param->type != fs_value_is_flag)
return invalf(fc, "%s: Unexpected value for '%s'",
desc->name, param->key);
result->boolean = true;
@@ -206,9 +203,6 @@ int fs_parse(struct fs_context *fc,
case fs_param_is_fd: {
switch (param->type) {
case fs_value_is_string:
- if (!result->has_value)
- goto bad_value;
-
ret = kstrtouint(param->string, 0, &result->uint_32);
break;
case fs_value_is_file:
diff --git a/include/linux/fs_parser.h b/include/linux/fs_parser.h
index dee140db6240..45323203128b 100644
--- a/include/linux/fs_parser.h
+++ b/include/linux/fs_parser.h
@@ -72,7 +72,6 @@ struct fs_parameter_description {
*/
struct fs_parse_result {
bool negated; /* T if param was "noxxx" */
- bool has_value; /* T if value supplied to param */
union {
bool boolean; /* For spec_bool */
int int_32; /* For spec_s32/spec_enum */
